I have a 30lbs pit puppy and he can escape the medium and large size ProValu Grate Crates. They are the only brand of dog crate sold at 3 of the larges grocery stores in my town, so I assumed it was a good purchase. I spent over $170 getting the two, one was for crate training and the other was for his bed/nighttime so i got the bigger one for that. Well he can easily slide the bottom liner out because theres only a flimsy metal bar that folds up that is stopping the liner from sliding out, so with almost no force it can be pushed down. Also once the liner is out he can tilt the cage and walk out the bottom because the gaps are so big. If I dont use zip ties on the doors he can easily move the door open and even push the door clips off. There are so many ways to escape these cages, theyre made to be collapsable but that also makes them extremely weak and easily knocked over and if your dog pulls or pushes on the walls even a little bit, it starts coming apart. Screw these over priced wireframe chunks of crap. User's recommendation: If you must use one, use zip ties to seal the walls together if your dog is over 20 lbs they can escape probably.